Insight into the effects of different oxygen heteroatoms on nicotine adsorption from cigarette mainstream smoke.

Cigarette smoke contains many chemicals, including nicotine, which is harmful and can cause health problems such as carcinogenesis disease, cardiovascular, respiratory, renal, and reproductive systems. Removal of nicotine from mainstream smoke can be done through adsorption with filters or solid adsorbents. In this study, we explored the use of activated carbons for the removal of nicotine from cigarette mainstream smoke. Activated carbons were prepared from dried hemp (Cannabis sativa) stem at an activation temperature of 350-550 °C using phosphoric acid as an activating agent. The results showed that the activated carbons with variable surface functional groups and porosity exhibited high efficiency for nicotine adsorption, removing 68-88% of nicotine from cigarette mainstream smoke. Through X-ray photoelectron spectroscopy and temperature-programmed desorption analyses, we identified that oxygen-containing functional groups, particularly carboxylic groups, exhibited a superior ability to adsorb nicotine. The computational analysis with DFT simulations further supported the importance of oxygen-containing surface functional groups in facilitating nicotine adsorption, with the carboxylic group providing the lowest adsorption energy among other functional groups.

Sulfur-Doped Carbons from Durian Peels, Their Surface Characteristics, and Electrochemical Behaviors.

Durian peels are an agricultural waste in Asian countries, including Thailand, Indonesia, and Malaysia, which can be used as a precursor for the production of activated carbon. The objective of this work is to produce activated carbon from durian peels by chemical activation using sodium sulfite (Na2SO3) as an activating and sulfur-doping agent. The process parameter investigated in this study was the activation temperature (500-900 °C) at a fixed impregnation ratio (durian to activating agent of 1:1, by weight). Specific surface areas and pore structures were determined by nitrogen adsorption and desorption measurements, and elemental compositions were characterized by CHNSO analysis. The chemical structure and surface functionality were examined by X-ray photoelectron spectroscopy. The electrochemical behavior of the obtained activated carbon was characterized in 6 M KOH using a three-electrode configuration. It was found that the sulfur content decreases with activation temperature. In contrast, the specific surface area of the activated carbon increases with activation temperature. However, the sample activated at 900 °C with the highest specific surface area (1499 m2 g-1) has a lower specific capacitance (166 F g-1) than the one activated at 700 °C (183 F g-1). This could be due to the presence of a pseudocapacitance caused by the organic sulfur functional groups such as thiophene, sulfone, and sulfoxide, which can trigger a surface redox reaction, leading to a higher capacitance.

Role of Nitrogen on the Porosity, Surface, and Electrochemical Characteristics of Activated Carbon.

Surface functionalities of activated carbon can be affected by the presence of heteroatoms such as oxygen, sulfur, and nitrogen. In this work, nitrogen-doped activated carbons (NACs) were prepared from shrimp shells, and the effects of the mixing ratio (raw material to an activating agent) on the porous texture and surface functionalities were investigated. It was found that, with increasing the mixing ratio (resulting in increasing N/C), the development of mesoporosity was significantly observed. This led to decreasing microporosity and specific surface areas (SSAs). The obtained NACs exhibited nitrogen functionalities in the forms of pyridinic and pyrrolic groups. It was found that although the pyridinic-N has a detrimental effect on the SSA, it does favor the pseudocapacitance, leading to an enhancement in the ion storage capability regardless of the low SSA.

Structural Coloration of a Colloidal Amorphous Array is Intensified by Carbon Nanolayers.

In this study, we introduce the possibility of applying a colloidal amorphous array composed of fine silica particles as a structural-color material to invisible information technology. The appearance of a thick filmlike colloidal amorphous array formed from fine silica particles is considerably influenced by incoherent light scattering across the entire visible region. Therefore, regardless of the diameter of the fine silica particles, the thick colloidal amorphous array exhibits a white color to the naked eye. When carbon is uniformly deposited in the colloidal amorphous array by a pressure-pulsed chemical vapor deposition method, incoherent light scattering in the colloidal amorphous array is suppressed. As a result, coherent light scattering due to the short-range order in the colloidal amorphous array becomes conspicuous and the array exhibits a vivid structural color. As structures, such as letters and pictures, can be drawn using this technology, the colloidal amorphous array as a structural-colored material may also be applicable for invisible information technology.

Photocatalytic performance of TiO2-zeolite templated carbon composites in organic contaminant degradation.

TiO2 composites with zeolite templated carbon (TiO2-ZTC) and activated carbon (TiO2-AC) were prepared and used as the photocatalysts for comparative studies with pure TiO2. TiO2-ZTC exhibited the highest rate of methylene blue degradation with a rate approximately 4 and 400 times higher than those of TiO2-AC and pure TiO2, respectively. Moreover, the highest catalytic performance of TiO2-ZTC in gas-phase degradation of acetone was approximately 1.1 and 12.9 times higher than TiO2-AC and pure TiO2, respectively. These outstanding performances could be attributed to high surface area, pore volume, and hydrophobic surface properties, leading to improvement in the adsorption properties of organic molecules.

Binderless thin films of zeolite-templated carbon electrodes useful for electrochemical microcapacitors with ultrahigh rate performance.

Controlled nanozeolite deposits are prepared by electrochemical techniques on a macroporous carbon support and binderless thin film electrodes of zeolite-templated carbon are synthesized using the deposits as templates. The obtained film electrodes exhibit extremely high area capacitance (10-12 mF cm(-2)) and ultrahigh rate capability in a thin film capacitor.